Automatic switch for use in telephone or like systems



R. N. SAXBY Jan. 21, 1936.

AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE SYSTEMS Filed Sept. 22,1932 M m t w B4 q v Z. w w

Jan. 2l 1936. N, SAXBY 2,028,689

AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE- SYSTEMS Filed Sept. 22,1932 6 Sheets-Sheet 2 Jmrz-wrae- 16241587 Mam/v 54x8)" 7 Jan. 21, 1936.

R. N. SAXEY AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE SYSTEMS FiledSept. 22, 1932 6 Sheets-Sheet 3 Jan. 21, 1936. R. N. SAXBY 2,028,689

AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE SYSTEMS Filed Sept. 22,1952 6 Sheets-Sheet 4 Arr Jan. 21, 1936.

R. N. SAXBY 2,028,689

AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE SYSTEMS Filed Sept. 22,1932 6 Sheets-Sheet 5 Arn .R. N. SAXBY 2,028,689

AUTOMATIC SWITCH FOR USE IN TELEPHONE OR LIKE SYSTEMS Jan. 21, 1936.

Filed Sept. 22, 1932 6 Sheets-Sheet 6 Patented Jan. 21, 1936 UNITEDSTATES 2,028di8t PATENT OFFICE AUTOMATIC SWITCH FOR USE IN TELE- PHONEOR LIKE SYSTEMS ware Application September 22, 1932, Serial No. 634,265In Great Britain October 14, 1931 11 Claims.

The present invention relates to improvements in automatic switches ofthe type used in telephone or like systems and is more particularlyconcerned with switches of the two-directional type arranged to havelongitudinal and rotary movement. Such switches as already extensivelyused in the telephone art are generally mounted with the wiper shaftvertical and have the operating mechanism above the contact banks andthe controlling relays above the operating mechanism. Since in a largetelephone exchange the number of such switches may run into thousands,the problem of mounting space hecomes of considerable importance, and itis desirable that the switches should be arranged to occupy as littlespace as possible consistent with proper access for maintenance andadjustment. The chief object of the invention is to provide a morecompact construction while at the same time reducing the number ofcomponent parts and simplifying assembly.

It has already been suggested to reduce-the height of such switches bymounting the operating mechanism and controlling relays within thevertical dimension of the banks but this arrangement has certaindisadvantages in that switches for different purposes may requiredifferent numbers of wipers and corresponding banks and consequently ifthe mechanism is accommodated within the limits of the minimum bankrequirements, when additional banks are needed there will be a certainwastage of space in view of the fact that the increase in the height ofthe switch applies also to the portion in which the mechanism isaccommodated, which space is Wasted. Accordingly, the present inventionaims at reducing the longitudinal dimension of the complete switch Whilestill keeping the maximum dimensions of the switch in a plane transverseto the switch shaft substantially equal to the dimensions of the banksand wipers.

According to one feature of the invention in an automatic switch of thetwo-directional type arranged for longitudinal and rotary motion thedriving magnets are mounted adjacent one end of the bank with their axesin the same plane transverse to the wiper shaft while the operatingmechanism is arranged in close proximity to this plane so as to reducethe longitudinal dimension of the switch without increasing the lateraldimension.

According to another feature of the invention, the contact sets usuallyprovided which are operated by the mechanical movement of the switchsuch as off-normal and cam springs lie in a plane transverse to thewiper shaft on the other side of the mechanism from the bank.

A further feature of the invention is the arrangement whereby the magnetfor producing longitudinal motion effects a release operation if it isagain operated after the switch has been rotated.

Still another feature of the invention relates to a mounting arrangementaccording to which the switch banks are permanently secured to thesupporting shelf and arrangements are provided for securing a switchmechanism to the bank together with means for ensuring the accuratecentering of the wipers relatively to the bank.

The invention will be better understood from the following descriptionof one method of carrying it into effect which should be taken inconjunction with the accompanying drawings comprising Figs, 1 to 11.

Fig. 1 is a perspective View of the operating mechanism of a switchconstructed in accordance with the principles of the invention; Fig. 2shows the manner in which the vertical magnet may bring about the rotaryrelease of the wipers; Figs. 3 and 4 show constructional details of a P.B. X. bank are built up of pressed metal plates; Fig. 5 shows the methodwhereby all mechanically operated springs are actuated through leverswhich engage with cam plates secured to the wiper carriage; this figurealso shows the P. B. X. bank are mounted in position in the form of agate which may be hinged away from the switch to give access to the mainbanks and wipers. Fig. 6 shows the operation of the vertical magnetinterrupter springs through the medium of a bell crank lever; Fig. '7shows a double vertical bank, and associated wiper blades fastened to anauxiliary wiper carriage which is operated from a collar clamped to themain Wiper carriage; Fig. 8 shows the manner in which the relay mountingplate is hinged to the rear of the cast frame member; Figs. 9 and 9ashow one method of securing the contact banks and switch mechanism tothe shelf particularly suitable for the construction shown in Fig. 1;Figs. 10 and 10a show another method of mounting the contact banks andswitch mechanism on the shelf which is somewhat simpler than theprevious arrangement, and enables certain components of the switch frameto be dispensed with, with the result that the mechanism is renderedmore accessible; while Fig. 11 shows the shape of the bank plates ifthis method of mounting is used.

As may be seen from Fig. l the switch comprises an upper die-cast framemember ID from the front of which are supported two vertical anglemembers i l and l 2 running parallel to each other and bridged at thetop and bottom by metal plates 53 and it between which the switch shafti5 is supported. In the construction shown the shaft is rigidly securedbetween the bridge pieces, that is to say, the upper end is accommodatedin a hole in the bridge piece 98 while the lower end passes through andis clamped to an auxiliary bridge piece 55 which in turn is fastenedacross the curved portion of the main bridge piece M. The object of thisarrangement is to enable the shaft and wiper carriage it supports to bereadily removable from the switch, and as will be appreciated from thedrawing this is eifected by uncoupling the auxiliary bridge piece l6 sothat the shaft and carriage may then be withdrawn downwards away fromthe switch.

The wipers of which only one set are shown designated ll are secured tothe tubular carriage member l8 which is adapted to slide and rotate onthe fixed shaft and also carries at its upper end the vertical androtary ratchet members. Movement is 'nparted to the tubular carriagemember it by means of magnet assemblies of substantially identicalconstruction which are mounted side by side on the die-cast frame i6,and in view of the different movements they are to produce one of themagnet assemblies is turned through an angle of approximately 99 andequipped with a different shaped pawl. In the drawings one magnetassembly only has been shown, that designated i9, which is located onthe right-hand side of the cast frame member and is intended to producerotary movement of the tubular carriage. As is the general practice themagnet assembly comprises a coil across the pole-pieces of which issuspended an armature 2i? rotatable about the pivot 2i, and arranged tobe attracted against the pressure of the fiat spring 22, the tension ofwhich is adjustable by means of the screw 23. To the extended arm of thearmature is pivoted a pawl 2 adapted to cooperate with the rotaryratchet member fastened to the tubular carriage. In respect of the othermagnet assembly which is of substantially identical construction, onlythe operating pawl 26 is shown and this is pivoted to the extended armof the armature and co-operates with the vertical ratchet member 27.

Considering now the detailed mechanical operations involved, when thevertical magnet is energized the spring-loaded pawl 26 runs up the lowerguide member 28 so as to engage with the vertical ratchet member 2?which is lifted until the pawl becomes locked against the upper pawlstop 29, in which position the tubular carriage and wipers will havebeen raised to the first level. During vertical stepping the carriage isretained in its operated position by means of a fiat spring detent 39shown below the operating pawl and lying between the lower pawl stop andanother stop member which limits the extent of its inward movement.

Rotary motion of the carriage is efiected from the other magnet providedwith a different shaped pawl 2d, the movement of which is guided betweenthe adjusting bollards 32 and 33 each capable of an eccentric movementon its fixing pillar which extends into the cast frame member. Thestroke of the rotary magnet armature is regulated by a further adjustingbollard 3Q which determines the resting position. At each rotary stepthe carriage is held in its operated position by means of a detentmember 35, shaped as shown, which is spring loaded so as to engage withthe ratchet teeth and adjustable as regards its resting position bymeans of the regulating bollard 36. On the first rotary step asemicircular plate 3'5 fixed immediately above the ratchet members onthe tubular carriage is arranged to enter a tooth on the comb member 38fastened to the frame, in order that the carriage and wipers may besupported when the vertical ratchet member rides out of engagement withthe holding detent 39.

Restoration of the carriage and wipers is effected in both directions ofmotion by a single helical spring 39 which encircles the fixed shaft andis contained in the tubular wiper carriage. The spring is secured at oneend to the shaft and at the other end to the wiper carriage, so thatduring the setting operation of the switch it is both compressed andtwisted, or alternatively stretched and twisted, depending upon themanner in which it is secured, in order to store up the energy necessaryfor the restoring movement in both directions.

Conveniently the wipers perform a so-called rectangular movement that isto say, when the switch is to be restored, the circuit is arranged sothat the wipers continue their rotation into an extreme position out ofengagement with the banks, whereupon the semi-circular plate 3? will.leave the comb member 38 and the tubular carriage is then restored byspring 3! to its normal position as regards the vertical movement. Inthis position the rotary ratchet 25 is lowered clear of the rotaryretaining detent 35, and the wipers are then rotated to the normalposition below the banks where the vertical ratchet memher 2? re-engageswith its holding detent 3i and also comes up against a fixed stop (notshown in the drawings) which is secured to the underside of the castframe member.

The wipers are of a particularly light construction arranged forclamping to the tubular carriage in the manner shown in the drawings,and comprise essentially two flexible metal blades 59 and ii of theshape shown, which are insulated from each other and the supportingbracket 52 by strips of insulating material and held together by meansof soft metal eyelets GS and i i the latter of which constitutes a cordhole.

In the case of P. B. X. working where large groups of lines areinvolved, it is ofen desirable for the wipers to be restored in a rotarydirection only in order that they may be raised into engagement with thenext level and in the absence of a release magnet particularly designedfor this purpose, the mechanism may readily be so arranged that there-energization of the vertical magnet at this time will bring about therotary release of the wipers.

The manner in which this may be effected is clearly shown in thedetached view, Fig. 2, from which it will be seen that the rotaryholding detent 35 is provided with a wedge-shaped extension 45 whichlies in the operating path of the vertical pawl 26, and accordingly whenthe latter is operated it runs up the inclined face of the extension 65and causes the rotary holding detent 35 to be lifted clear of the rotaryratchet member 25. With this construction the rotary holding detent willbe lifted clear of the ratchet teeth during each vertical step but thiswill not upset the operation of the switch since the detent is withoutfunction during this period.

In the case of P. B. X. Working where a number of small groups areinvolved comprising for example 10 lines or less in each group, theswitch will preferably be provided with what is known as a P. B. X. bankarc on which the required grouping is determined. Hitherto such a P. B.X. bank arc has generally been constructed as a substantiallysemi-circular metal plate carrying rows of screws which serve as thecontact points, and are wiped over by one or more auxiliary wiperscarried on the switch shaft, the plate itself being connected to earthand. the last line in each particular P. B. X. group being marked by theremoval of the relevant screw. This construction however is somewhatexpensive owing to the necessity of tapping 100 holes and fitting therequired screws. In the present construction it is proposed that thebank arc shall be built up of stamped metal plates carrying projectingcontacts such as shown in the detached view in Fig. 3, the pairs ofplates constituting a single level being separated from each other by aninsulating strip 8? of substantially the same shape but without theindentations formed by the projections. The respective pairs of platescomprising the complete bank are assembled between collars turned on thepillars 46 and 41, and are locked in position by a skewer pin 48 whichpasses through all the plates. The marking of the last pin in each P. B.X. group is efiected by breaking off the particular contact concernedand for this purpose the contacts are suitably reduced in cross sectionat the point where they join the plate to enable its operation to becarried out in a simple manner.

Although it might appear that this arrangement does not offer the sameflexibility as the screwed pin arrangement since when once a contact isbroken off it cannot be replaced, it should be explained that theapparent disadvantage is more than ofiset by the cheapness of theplates, and the ease by which they may be removed and replaced byanother set. Removal of a particular pair of plates may be made bywithdrawing the skewer pin 48, after which the plates concerned areslipped out of engagement with the supporting collars without upsettingthe arrangement of the other plates in the bank. With this arrangementit will be evident that re-distribution of the P. B. X. groups whendesired may be carried out in a simple manner. All plates areelectrically connected together through the mounting pillars 45, 4'! andthe skewer pin 48 and the insulating strip between the plates of a pairmerely serves the purpose of preventing the upper wipers from engagingthe same contact as the lower wipers when the last line in a group isencountered. Its function in this respect will be readily apparent fromFig. 4 which shows a typical level of 20 contacts split up into fourgroups in the manner suggested by the brackets, and determined bybreaking ofi? the 7th and 10th contacts in the upper level and the 8thand 10th contacts in the lower level. The wipers are showndiagrammatically as standing on the last line of the first group in theupper level, where it will be seen that the leading wiper blade 49 isprevented from engaging the same contact as the lower wiper blade 5c bythe separating strip of insulating material 8?.

Preferably in this construction the assembled bank is provided in theform of a gate shown as 5! in Fig. 5 which is hinged on the pin 52 to abracket 53 fastened to one of the bank rods 54. Normally the bank willbe swung into position and locked by a suitable catch so as to lieconcentric with the P. B. X. wipers 49, 50 and 55,

but when access is required to the main banks and wipers the completearc is hinged outwards away from the switch. The P. B. X. wipers aresecured to the tubular carriage in the same manner as already describedfor the main switch wipers, and are of similar construction except thattwo pairs of blades are provided in one assembly and are shaped so thatthe contact end of both pairs may lie in the same plane and engage withthe same level of contacts. All four blades are electrically insulatedfrom one another, and by means of the ZOO-point bank it is possible toprovide P. B. X. facilities over 260 lines, which are split up into anynumber of groups with the proviso that each group shall contain not lessthan two or more than ten lines. The complete ZOO-point bank occupiessubstantially the same space as the 100-point bank hitherto provided,and as it is built up of separate pairs of plates which are complete inthemselves it offers considerable economy in cases where a small numberof P. B. X. groups are required since only the levels of contacts whichare actually necessary need be provided.

All mechanically-operated springs are mounted at the top of the switchon a common plate which is readily removable as a single unit oralternatively the spring sets themselves may be bodily removable bywithdrawing the associated bracket fixing screws. Only one fixing screwneed be provided in which case the opposite end of the bracket will beprovided with a bumped-up projection which registers with a hole in theplate so as to line up the spring set in its proper position. The commonplate which is assumed to br dge the switch frame may be seen in Fig. 5marked 58 and for convenience in drawing it is shown as carrying onlyone set of springs designated 57, although it will be appreciated thatactually a number of such sets are provided which are fastened in lineacross the plate. These springs are arranged to be operated from leversof the various shapes shown which pivot on the pins shown dotted, andare actuated from the plates 53 and 59 carried by the wiper carriage.Actually the plate 53 is modification of the semi-circular plate 3'!shown in Fig. l and to this extent Figs. 1 and 5 do not strictlycorrespond. Th plate 58 however performs the same function of supportingthe carriage during the rotary movement and also serves for operatingvarious mechanical spring sets. The additional plate 59 lying on top ofthe plate 58 is provided for the purpose of operating what are known asnormal post springs and is supported by the wiper carriage but is freeto rotate independently thereof about the shaft, so that it partakes ofthe vertical movement only but is not influenced by the subsequentrotary movement of the carriage during the normal setting of the Wiperson to the desired contacts. For facilitating the understanding of thearrangement, the plates 58 and 59 and associated wiper carriage areshown as withdrawn downwards away from the spring operating levers, andthe dotted extension lines are intended to indicate the position takenup by the levers when the assembly is in its normal position.

Considering now the mechanical operations involved, it should beexplained that with the wiper carriage in its normal position the endface 58a of the projection on the plate bears against the extended armof the off-no... al-spring-operating lever N at the point 6% thei ebyholding the spring set in its normal position under strain.

When the wiper carriage is raised during the first vertical step, theextension Eta of theplate 58 is raised clear of the lever 'N so that thelatter then moves under spring pressure in the direction indicated bythe arrow to enable the onnormal spring assembly to take up its operatedposition.

When a level is attained at which the operation of normal post springsis necessary, one or other of the stepped extensions on the plate willbear against the rollers 5! or 82 fastened to the operating levers NPlor NPZ, either or both of which will then be tilted in the directionindicated by the arrows to operate the respective spring assembliessubstantially identical to 5'7. It will be seen from the drawings thatthe operating rollers on the levers NH and NP? may be secured in any oneof ten positions depending upon the level on which the operation of thenormal post springs is desired.

Spring combinations of any well-known type may be employed but those ofthe anti-bounce type shown in the drawings are preferred. Theanti-bounce characteristic of these springs is attained in the presentinstance by considerably reducing the efiective length of the stationaryspring arms in the combination. For this purpose the clamping plates atboth ends or the assembly and also the separating insulators employedare provided with the extension 63 which serves to hold rigid a certainportion of the stationary springs in the assembly to enable the desiredresult to be achieved.

When the wipers take their first rotary step into engagement with thebanks, the plate 58 makes a clockwise movement and the operating rollerEd of lever NR which is accommodated during the vertical movement in thegroove 65 is now caused to ride out on to the circumference of the platethereby operating the normal rotary set of springs shown.

In case the switch is functioning as a group selector and all theoutlets on the level selected prove busy, the wipers will be eventuallymoved to their 11th position which is unwired as regards a trunkconnection, and in order that the condition of the circuit may bealtered accordingly, the extension 58a of the operating plate is causedto come into contact with the roller 66 of the lever S which thereupontakes a movement in the direction indicated by the arrow to operate thecam springs.

No further changes take place in the condition of the mechanicallyoperated springs until the switch is released in the manner alreadydescribed, and accordingly when the wipers are moved into their 12thposition the point 58b on the operating plate will move clear of thesupporting comb 38 so that the wiper carriage commences to fall to itsvertical normal position. At the same time the movement of the operatingplate 58 into its 12th position causes the extension 58a to move awayfrom the operating roller 66 on the lever S so that the cam springs areimmediately restored, while moreover the slot 580 will now be setopposite the operating roller 6% of the lever NR which recedes thereinand brings about the restoration of the normal rotary springs.

In order that the normal post springs shall also be released at thistime a pin 38 which is let into the plate 53 is arranged to engage thelefthand end of the lever 59 which thereupon moves a short distance in aclockwise direction so that its right-hand end moves clear of theoperating rollers 5i and 62 and levers NH and NPZ are allowed to recedeto restore the respective spring sets.

When the carriage has fallen to its normal position the rotary holdingdetent is no longer in engagement with the rotary ratchet member and aspreviously explained the wipers are then rotated back to normal by therestoring spring. In order to ensure that the normal rotary springs arenot again operated during the return movement of the wipers below theblanks, the respec tive operating rollers 66 and 64 are reduced indiameter at their lower ends sufficient to clear the plate 58.

When the wiper carriage arrives in its fully restored position, theextension 58a of the operating plate comes into contact with theextension on the lever N and rides along its face for a short distance,during which time the lever is again tilted to restore the ofi-normalsprings to their normal condition. It will be noticed that the operatingarm of the lever N is provided with an extended lip which is bent over,and this enables the proper functioning of the lever in relation to theoperating plate 58 when the wipers are restored in a vertical directiononly without having previously performed their rotary movement as willappear in connection with the digit absorbing feature to be describedlater.

The vertical and rotary interrupter springs although not shown aremounted at opposite sides of the common plate and operated direct fromthe magnet armatures. The operation of the rotary interrupter springswill be readily appreciated from reference to Fig. 1 when it isexplained that the armature 20 is provided with an arm extendingvertically arranged to actuate directly the associated spring set whichis preferably mounted at the extreme right-hand side of the commonplate.

The actuation of the vertical interrupter springs presents rather moredifficulty since if they are to be mounted at the extreme left-hand sideof the common plate it is necessary that the vertical movement of thevertical magnet armature shall be converted into a horizontal movementin order that the springs may be operated in a manner similar to theothers mounted on the plate. For this purpose it is proposed to employ asmall bell-crank lever it of the shape shown in the detached View, Fig.6, which will be pivoted on the pin 59 screwed into a convenientposition in the switch frame. One arm of the bell-crank lever '50 isarranged to bear on a small projection II on the vertical magnetarmature while the other arm is provided with an insulated bufier and isarranged to bear against the spring set to be operated. At each movementof the vertical magnet armature, the bell-crank lever is rocked and theassociated spring set is therefore operated with a horizontal movementin a manner appropriate to its fastening.

It the switch is to be used in circumstances where absorption of one ormore of the setting digits is desirable, it will be preferable toarrange for the release of the carriage and wipers in a verticaldirection only, in order that they may be restored to their normalposition in the minimum amount of time so as to be ready for the nexttrain of impulses. It will be realised that under these conditions thereleasing time must always be less than the pause provided betweensuccessive trains of impulses, and the rectangular release operationemployed in ordinary w king would seriously reduce the margin of safetyin this respect. In order to obtain direct vertical release the switchis provided with an auxiliary magnet of small dimensions as comparedwith the main driving magnets, which is preferably mounted below thecast frame and is arranged upon operation to move the vertical holdingdetent 30 out of engagement with the vertical ratchet member so that thecarriage and wipers immediately fall to the normal position. Thenecessity for the turned over lip on the off-normal-spring-operatinglever N as shown in Fig. will now become apparent, since when theprojection 58a. of the operating plate falls against the end of thelever N it will ride over the inclined portion, so as to bring about themovement of the lever which is necessary to restore the off-normalspring sets to their normal condition.

Vertical wipers and banks when required will be provided in the mannershown in Fig. '7 and comprise essentially a vertical wiper carriage 12arranged to slide on the guide bar '13 which is preferably securedbetween the underside of the frame casting and the lower bridge pieceshown in Fig. 1. Two sets of wipers and banks are provided which areinsulated from each other so that 20 separate contact points may beclosed in pairs. The vertical bank M which is doublesided is fastened toone of the bank rods or alternatively to one of the side angle memberssuch as 12 in Fig. l, and comprises two rows of ten contacts and twometal plates such as l5 arranged back to back. Fastened to the verticalwiper carriage are the wiper blades it and i? arranged to slidevertically over the bank so as to connect the respective contacts inturn to the metal plates, thereby completing the electrical connection.The vertical wiper carriage is coupled by means of an extended limb '58to a channelled ring 19 clamped to the main wiper carriage in the mannershown, and it will be appreciated from this arrangement that thevertical carriage will be caused to take the vertical setting of themain wiper carriage but is not influenced by the subsequent rotarymovement.

The controlling relays are secured to a mounting plate of the well-knowntray-shaped construction designated 89 in Fig. 8 in which the relays arenot shown in detail but the position they occupy is indicated by dottedlines. As illustrated the mounting plate is arranged to pivot on thescrews 8! one on each side of the cast frame and is locked in positionby the screws. With this arrangement when the switch is removed from theshelf the relay plate may be hinged backwards in the manner shown togive access to the mechanically operated springs mounted immediatelybelow. This feature of hinging the relay mounting plate is notabsolutely essential but it is a facility which is easily provided withthe present construction. The condensers 32 are mounted at the back ofthe relay plate in the manner shown on a second plate 83 which isL-shaped and pivoted at the point 84, and is arranged to clip intoposition by means of bumped-up portions on the lugs 85 which spring intoslots cut in the sides of the relay mounting plate. Access to the wiringat the rear of the relay mounting plate may be had by pulling the plate83 from the bottom so that it hinges at the point 84 outwardly. It willbe appreciated therefore that the plate 83 in addition to supporting thecondensers also completely encloses the rear of the relay mounting plateand therefore acts as a dust cover. The main dust cover (not shown)which is fitted over the front of the switch is arranged to envelop boththe relays and the switch mechanism, and is support-ed on the guideplate 8% riveted to the top of the relay plate, and clipped in positionbehind the pins ill and 88. Preferably the spring connecting jack willbe mounted on the back of the plate which carries the mechanicallyoperated springs and as the relay mounting plate is arranged to beremovable therewith it will be appreciated that all electrical wiringmay be made quite apart from the mechanical movement.

One arrangement of mounting the contact bank and switch mechanism on theshelf is shown in Figs. 9 and 911 this arrangement being particularlysuitable for the construction illustrated in Fig l. The shelf is shownin Fig. 9a and is arranged as a two-piece construction comprising at thetop a pressed plate 83 bent at right angles and below a flat plate 85.supported at its ends by substantial bracket members 98. The upper shelfmember 58 supports along its vertical side the shelf jacks 9!, while thelower shelf member 89 is movable so as to be suitable for one, two orthree banks depending upon the capacity of the switch. In the drawingsthe banks are shown as clamped together in a single unit and althoughthis is not absolutely necessary an appreciable saving is effected inthe vertical dimension by the elimination of intervening clamping nuts.As is the general practice the banks are threaded on to rods such as 52th ends of which extend above and below the mounting shelf to provide alocating means for the mechanism and controlling relays. Conveniently agroove is turned in the upper ends of these rods to accommodate a springclip 93 of hairpin shape which is inserted between the upper bank plateand shelf member 88 to hold the rods in position. If the banks arerequired to be additionally secured to the shelf this may be effected byextending certain of the clamping bolts through holes in the shelfmembers. The mechanism shown diagrammatically in Fig. 9 is provided withtwo holes in the base of the cast frame member which accommodate theupper ends of the bank rods, while the lower ends are clamped intorecesses in the lower bridge piece 85, corresponding to E4, Fig. 1, bymeans of the hooked clamping members 96, in a manner which may be morereadily appreciated from the perspective view, Fig. 1. With thisarrangement the switch is readily removable from the shelf and noinconvenience is caused in lining up when it is replaced since theclamping means are selfcentering.

When the switch (Fig. 9) is in its mounted position on the shelf (Fig.9a), the base of the cast frame member seats itself on the shelf plate88 and the switch jack 9? comes into register with the springs of theshelf jack 9!, to complete the electrical connections.

Another method of mounting the contact banks and mechanism on the shelfis shown in Figs. 10 and 10a, from which it will be seen that thevertical angle plates (Fig. 10) extending from the front of the switchare now dispensed with, and the bank rods 98 are threaded directly intothe base of the cast frame member 99, and carry at their lower ends thebridge piece I 95 which serves as the lower support for the fixed shaftand wiper carriage indicate by the dotted lines. The light shelf membersused in the previous arrangement are replaced by a single sturdy memberlol (Fig. 10a), preferably a length of angle iron of suitable crossconnection, arranged to carry along its vertical side the shelf jacksI02. The contact banks are constructed as a single unit and are providedwith extended clamping bolts so that they may fasten directly to theshelf.

To provide a means for correctly locating the mechanism when it ismounted in position on the shelf, the holes in the upper and lower bankplates E53 and l c4 are slotted in the manner shown in Fig. 11sufficient to pass the turneddown portion of the bank rods. With thisarrangement the mechanism will be positioned over the shelf by ahorizontal movement and then lowered until the base of the cast framemember 89 seats itself on the shelf ml. In this position the switch jackm5 registers with the shelf jack m2, and the large diameter portions ofthe bank rods enter the holes in the bank plates thereby lining up thewipers with the banks.

In case the switches are to be transported from one place to another inposition on the racks they may be definitely locked in place by means ofa securing screw which passes through a hole in the switch frame and isthreaded into the mounting shelf lfll.

The second arrangement of mounting is to be preferred in that the frontangle plates H and i2 shown in Fig. 1 are dispensed with, and it istherefore possible to remove the vertical members on the cast frame towhich they were secured, thereby considerably opening up the switchmechanism and facilitating adjustment. When this is done the upperbridge plate l3 will also disappear in the form shown, and will bereplaced by an auxiliary bracket member secured to the top of a pillarextending upwards from the cast frame in substantially the positionoccupied by the comb member 38 for which it will also serve as asupport.

In order to effect a still further increase in the speed of operation,the vertical and rotary movements may be arranged as separate units andquite distinct from each other, so that in operation the verticalmovement will not be burdened by the weight and parts having a purelyrotary function, while similarly the rotary movement will not beburdened by parts having a purely vertical function. The reduction ininertia thus obtained should enable higher hunting speeds to beobtained.

According to the invention therefore, an improved switch is provided, ofparticularly co'mpact design and constructed of a plurality of unitswhich are complete in themselves thereby offering distinct manufacturingadvantage over similar type switches hitherto constructed.

I claim:

1. An automatic switch having a wiper shaft and mechanism for moving thesame in a vertical and rotary direction, a plurality of contact springsets, means for operating said springs by the mechanical movem nt of theshaft, said spring sets mounted in a plane transverse to the plane ofthe wiper shaft, and means for operating said sets at differentpositions of the wiper shaft.

2. An automatic switch having a wiper shaft movable in vertical androtary directions, a magnet having means for moving the shaft in avertical direction, and means operated by said magnet after the shafthas been moved in its rotary direction for releasing the shaft.

3. An automatic switch having a bank of contacts, a wiper shaft, meansfor moving the shaft in a longitudinal and rotary direction, means forreleasing the shaft, said means effective tocause a forward rotarymovement, a longitudinal movement and a return rotary movement if re-'lease is initiated after a rotary movement of the shaft has taken place,and to cause the shaft to release over the same path over which it wasoperated in case release is initiated before rotary movement thereof hastaken place.

4. An automatic switch having a bank of contacts, a shaft carryingwipers cooperating therewith, means for operating said shaft in avertical and rotary direction to bring said wimrs into engagement withcertain contacts of said bank, an auxiliary wiper, an auxiliary bank ofcontacts therefor mounted on the front of the switch, said auxiliarybank pivotally mounted and adapted to swing out to permit access to thefirst bank and wipers.

5. An automatic switch as claimed in claim 4 in which the auxiliary bankcomprises a plate for each longitudinal step of the switch, each platehaving projections corresponding to each rotary step of the switch, eachprojection having a weakened portion permitting breaking 01f ofprojections readily.

6. An automatic switch having contacts, a wiper shaft, a tubularcarriage slidably mounted on said shaft and also movable in a rotarydirection thereon, wipers mounted on the carriage, and a single helicalspring for restoring the carriage in both directions of movement.

7. An automatic switch as claimed in claim 6 in which the wipers aresecured to the carriage by soft metal eyelets, one of said eyelets ofsufficient diameter to form a cord hole through which wires leading tothe wipers may pass.

8. An automatic switch having a switch shaft carrying wipers, means formoving said shaft in longitudinal and rotary directions, a spring setoperated when the shaft moves off normal, another spring set operatedwhen the shaft takes its first rotary motion, otherspring sets operatedin different positions of the shaft, and a single member for operatingall of said sets.

9. An automatic switch having contacts arranged in levels, a shaftcarrying wipers cd-operating with the contacts, means for raising theshaft step by step to different levels and means for rotating the shaftto carry the wipers over the contacts of a level, means controlled bysaid first means for releasing the shaft in its rotary movement onlywithout releasing the shaft in its vertical movement, said first meansthereafter operable to raise the shaft to bring the wipers to the nextlevel.

10. An automatic switch having contacts, a wiper shaft carrying wipersfor engagement with any of said contacts, a magnet having a pawl forraising the shaft, a magnet for rotating the shaft, a rack of ratchetteeth engaged by the pawl of the first magnet to raise the shaft, saidrack being attached to the shaft in such a manner that it is moved outof range of the pawl when the shaft is moved in its first rotarymovement.

11. An automatic switch having contacts arranged in levels, a shaftcarrying wipers, means for operating the shaft to a level and rotatingthe same to step the wipers over the contacts of a level, auxiliarywipers, a pair of toothed plates for each level, a strip of insulationseparating each pair, said insulation preventing the auxiliary wipersfrom both engaging the remaining tooth when another tooth is broken offin a particular position.

ROBERT N. SAXBY.

